Working on the user interface presented us with a considerable challenge in view of the amount and variety of textbook material, as well as the occasional absence or incompleteness of relevant data. Some compromises and simplifications were necessary, which will be explained in more detail in the following lines.

2.1 Criteria for the selection of textbook material

The criteria for the selection of textbooks included in the database were somewhat arbitrary. This applies especially to the beginning of the period in question, when the gap between the prescribed material and the texts that teachers and priests used to teach the youth was often significant. The gap between the prescribed textbooks and everyday practice gradually decreased during the period considered. In textbook material from the second half of the nineteenth century, especially in that which was created after 1869, there are significantly fewer outlined deviations. In the following lines, we will focus further on the criteria we used to classify the textbook material in the database.

1. The bibliography is time-bound by the General School Ordinance from 1774 and the dissolution of Austria-Hungary in 1918. Naturally, some of the texts that were used in school lessons in the Theresian and Josephinian eras (and often later) were written before 1774. We included such textbooks in the review only where their use in the period after 1774 was sufficiently attested in sources and literature. It is, admittedly, possible, and indeed probable, that other older texts were also in use during that period. However, this is still open to further research. Even the year with which we conclude the bibliography was by no means an impenetrable barrier. Quite the contrary! Many textbooks were published in a more or less modified form also in the new state framework.³ In such cases, we also mention editions from the period after 1918 in the notes.
2. The area in question was part of the Habsburg Empire for most of the period under consideration. The exception is the period between 1809 and 1813 when parts of these lands were included in the French Illyrian provinces; we included the textbooks published during that era in the bibliography as well.
3. Because the research project focused mainly on the development of Slovene nationalism, and due to time and practical limitations, we did not include a significant part of the textbooks and teaching aids in the Latin, German, Italian, Hungarian, and Croatian languages ​​in the database. We are aware that this is why a large part of the textbook material that was in use at major schools (Hauptschulen), normal schools (Normalschulen), and (later) either at so-called utraquist or bilingual elementary schools or at elementary schools (Volksschulen) with German or another language of instruction, and especially at high schools and Realschulen, is missing. In the future – either as a supplement to this publication or as part of further research – this material will undoubtedly need to be analyzed in more detail and included in the present corpus of textbook material.
4. The decision to focus in this phase on the collection and classification of textbook material, which came into consideration during compulsory education, is also related to the above limitations. Thus, we focused on textbook material intended for primary schools–primary school, according to the definition used by Bogo Grafenauer in Zgodovina Slovencev [History of Slovenes], is understood as "a school which does not require any previous education, educates everyone in their mother tongue and gives them basic knowledge, regardless of their social affiliation and future profession"⁴–and to lower secondary schools. Textbooks intended for lyceums, high schools,⁵ and Realschulen, as well as materials that were used in teachers training colleges (Lehrerbildungsanstalten) and vocational schools, are therefore not included. ⁶

Indeed, the duration of compulsory education in the period in question was anything but stable, thus the decisions regarding the inclusion and exclusion of textbook material are always at least somewhat arbitrary. Compulsory education was initially limited to the period between the ages of six and twelve years by the General School Ordinance from 1774.⁷ Even if there was no compulsory education in the Illyrian provinces, we took into account textbook material intended for schooling at the primary and (at least) lower secondary level for this short-term intermezzo – in addition to the textbook material intended for the newly formed uniform four-year primary schools – for the sake of a relatively manageable corpus of material and in the face of sudden changes in the field of secondary education⁸. After the restoration of Habsburg power, the school system on the territory of the former Illyrian provinces was restored to its previous state. With the decree of the Study Court Commission of September 27, 1816, compulsory education was extended and ended with the completion of fifteen years of age, whereby in the newly added period, as Schmidt points out, "only Sunday lessons were obligatory." ⁹ With the liberal school reform in 1869, the tendency towards a general eight-year compulsory school attendance came into force. The ideal of eight-year compulsory education was fully implemented only in Styria and Carinthia, but not entirely in the other provinces included in this bibliography. The right to shorten compulsory school attendance was given to:

• Princely County of Gorizia and Gradisca, where the provincial school board was allowed to "shorten compulsory education to five years (from completed age of seven years to completed age of twelve years) in those school districts where local conditions would require it"; ¹⁰
• Istria, which opted for a "six-year compulsory education (from completed age of six years to completed age of twelve years) with review school (Wiederholungsschule) in the winter to the completed age of fourteen years"; ¹¹
• Carniola, where compulsory education was determined by the Law on how to regulate the management, maintenance, and attendance of elementary schools, as follows: "The duty to go to school (school duty) starts from the age of six and lasts, as a rule, until the age of twelve, and until the age of fourteen in cities and towns with schools that have three or more classes. With regard to special local circumstances or the climate, the district school authority may exceptionally allow that school duty begins only after the completed age of 7 or 8 years. In the same manner, the district school authority may allow children who have reached the age of twelve years and have completely learned their school subjects to be dismissed from school in cities and towns as well".¹² In Carniola, the outlined changes were implemented only in 1873, and in 1870 in the remaining provinces included in our bibliography. ¹³

2.2 Authors, co-authors, translators, and editors

Especially in the earlier period, the records of authors' names and surnames were often inconsistent. In different editions of the same textbook or different textbooks by the same author, we often have to deal with different records of the authors' names and surnames. To a certain extent this is the result of changes in transcription, and partly the result of a decision to write the name in another language. It also happens that the author, to whom the authorship of the textbook can be attributed with a considerable degree of certainty based on sources and existing research, is not even mentioned in the textbook. Since strictly following the original inscriptions in each textbook would therefore cause unnecessary confusion and make it difficult for the user to perform a search, we have always used the standard version of the name and surname records. In doing so, we relied in particular on Slovene Biographical Lexicon and the Slovene library information system Cobiss as well as other relevant literature on the subject.

In addition, for the sake of transparency, we listed the original authors separately – field: "Original author (if it is an adaptation) / Author (if it is an original work)" – and authors of later adaptations, translators, and editors – field: "Author of the adaptation / Translator / Editor." It must be pointed out in this regard that the distinction between the author of the original and the adapter is not always completely unambiguous. Some textbooks were published for a very long period of time. In such cases, the many rewritings of the textbook (many of which were created even after the death of the original author) could be regarded as an independent work without any particular reservations, and the author of the adaptation could be considered an author in the true sense of the word. Indeed, such decisions are always at least somewhat arbitrary. In order to avoid inconsistency, we decided on an approach according to which, even in cases of major revisions, we kept all later editions of a textbook in the same entry – in cases where we decided otherwise, we explained our decision to treat the textbook independently in the notes. Since numerous textbooks are translations, we have always listed translators in addition to the original author. The line between editor and author is often blurred. Especially in the case of readers and songbooks, the individual cited as the author was often not the author of the selected texts, but only a sort of editor. We only mentioned the editors in exceptional cases, when they were listed next to the author.

2.3 Titles¹⁴

In the field "Title (first edition)" we indicate the title of the first edition, or if this is unknown, the title of the first edition for which we have accurate title information. In some cases, it happens that we know from the reports of contemporaries that the textbook was published earlier, but the first edition has not been preserved. At times it also happens that otherwise reliable sources, which talk about the textbook being published, do not contain information about the exact title. In such cases, we did not specify approximate titles. We have consistently adhered to the principle of keeping the title record – if at all possible – in its original form. Since the year is always added to the title, the reader will easily find out whether it is the title of the first edition or the first known edition of the textbook.

We list the known titles of all subsequent editions in the field "Title (subsequent editions)." Even in this case, it often happens that we know for sure that it existed – in this case, mostly based on the mentions of the previous, inaccessible editions at the beginning of one of the textbooks that we had at our disposal. Therefore, in some parts there is a discrepancy between the number of years indicated in the field "Year (later editions)" and the years that are written in parentheses next to the different versions of the title. In this case also we have always tried to preserve the original format of the title. Years in parentheses refer to editions with the same title.

2.4 Places of publication

Records of places of publication underwent many changes during the period considered. In part, it is a consequence of the absence or insufficient standardization of the language in which the textbooks used in the area considered were written. This is further complicated by the fact that the place was often written in Latin, German or some other language. In order for the present bibliography to be sufficiently transparent and, more importantly, to enable the user to use the database more efficiently, we have used the modern English versions of place names at all times.

In the field "Place (first edition)" we indicate the place of the first known edition. Locations of all other editions are indicated in the field "Place (later editions)". In relation to writing years in parentheses, the same rules apply as when listing titles.

2.5 Publishers

Changes and inconsistencies are even more pronounced when listing publishers than when listing place names. Standardization was necessary in this case as well. We realize that the way the name of the publisher was written (the same applies to the place name) is important and as such could be the subject of historiographical analysis, but in this case, ease of use prevailed over any such concerns. What is more, such a decision was also a consequence of the fact that we often relied on entries in the Cobiss library information system due to the abundance of material. Although the entries on the aforementioned system generally preserve the original notation, standardization still occurred, so that the recording of the original form of the publisher's name would not always be possible in any case. When standardizing, we mostly followed the record found in the Slovene Biographical Lexicon; when dealing with earlier periods we relied principally on the work of Anja Dular, Vlado Schmidt, and Ivan Andoljšek. ¹⁵ When working on textbooks from Prekmurje, we drew on the work of Ivan Škafar. It should also be noted that in the case of Prekmurje the names of the publishers are listed first, followed by the surname. Thus, we followed the record that is in line with our standard, and not the original order. We have also at all times standardized the records of those publishing houses whose names did not derive from the personal name of the publisher. The place of the first known edition is indicated in the field "Publisher (first edition)." The places of publication of all other editions are indicated in the field "Publisher (subsequent editions)". In relation to writing years in parentheses, the same rules apply as when citing titles and places of publication.

In cases where the name of the publisher is unknown, the name of the printer is given. In the rare cases where we have not been able to identify even the latter, we provide information about the bookshops or booksellers where the textbook was sold and related information.

2.6 Year of publication

In certain instances, we only have information about the year of publication, but not other information about a textbook. In such cases, the year of publication is provided only in the "Year of publication" field, but not elsewhere. Therefore, in some places there is a discrepancy between the years, which are listed in the other fields. Although it is very likely that in such cases all other information was also often the same – i.e., title, place, and publisher – this cannot be stated with certainty.

For textbooks that began to be published after 1869, we only indicated the period of validity of the textbook and not each reprint separately, since reprints of some textbooks were published almost every year, but the content did not change.

2.7 Data on the use of textbook material

The information about the purpose of the textbook material, which is listed in the "Subject" field, is intended exclusively for the basic orientation of the reader but cannot be the basis for a more detailed analysis of the use of textbooks. In everyday practice, the use of textbooks did not always correspond to their original purpose, in addition, the names of some subjects and the subjects themselves changed over time. For a more precise insight into the use of an individual textbook, readers can help themselves with the bibliography listed in the "Sources and bibliography" section. For the period after 1869, a precise insight into the purpose of the approved textbooks is also provided by the materials of the Ministry of Education. Links to relevant material are also available in the "Sources and bibliography" section.